The problem of turning of SCRs in capacitive discharge ignition systems is well known. A number of patents have addressed shutting down the anode to cathode current from the source charging the storage capacitor. These have all related to direct current to direct current converter power supplies which can be electronically shut-down. See, for example, U.S. Pat. Nos. 3,583,378; 3,800,771; 3,838,328; and 4,069,801. The output of an alternator or generator cannot be switched off as can direct current converter power supplies. The output being an alternating current will periodically pass through zero. At this time, the SCR will shut down. However, it is desired to shut down the SCR immediately, that is, without waiting for the next polarity reversal of the alternator or generator. The applicant's circuit is directed to the shut-off of the power SCR in a capacitive discharge ignition system supplied by a generator or alternator.